Effect of Gravity on Axial Development of Vertical Bubbly Flow

2006 ◽  
Author(s):  
Kazuya Abe ◽  
Yoshinori Hirose ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Takashi Hibiki
Keyword(s):  
Liquid Velocity ◽  
Constitutive Relations ◽  
Bubbly Flow ◽  
Interfacial Area ◽  
Stereo Image ◽  
Microgravity Environment ◽  
Axial Distance ◽  
Two Phase ◽  
Flow Measurements ◽  
Interfacial Area Transport

In relation to the development of the interfacial area transport equation, axial developments of void fraction profile, bubble number density, interfacial area concentration and Sauter mean diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured by using a Stereo Image-processing Method under normal- and micro-gravity environment. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter = 5, 20, 40 and 60) under various flow conditions of superficial gas velocity (0.00823–0.0303 m/s) and superficial liquid velocity (0.138–0.915 m/s). The interfacial area transport mechanism under microgravity environment was discussed in detail based on the obtained data and the visual observation. These data can be used for the development of reliable constitutive relations which reflect the rigorous transfer mechanisms in two-phase flow under microgravity environment.

Interfacial Area Transport of Bubbly Flow Under Microgravity Environment

2003 ◽  
Author(s):  
Norihiro Fukamachi ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Takashi Hibiki ◽  
Mamoru Ishii
Keyword(s):  
Liquid Velocity ◽  
Constitutive Relations ◽  
Bubbly Flow ◽  
Interfacial Area ◽  
Visual Observation ◽  
Microgravity Environment ◽  
Axial Distance ◽  
Two Phase ◽  
Flow Measurements ◽  
Interfacial Area Transport

In relation to the development of the interfacial area transport equation, axial developments of one-dimensional void fraction, bubble number density, interfacial area concentration, and Sauter mean diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured by using an image-processing method under microgravity environment. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter = 7, 30, 45 and 60) under various flow conditions of superficial gas velocity (0.0083 m/s ∼ 0.022 m/s) and superficial liquid velocity (0.073 m/s ∼ 0.22 m/s). The interfacial area transport mechanism under microgravity environment was discussed in detail based on the obtained data and the visual observation. These data can be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow under microgravity environment.

Measurement of Local Flow Parameters in Vertical Upward Bubbly Flow at Normal- and Micro-Gravity Conditions

2008 ◽  
Author(s):  
Akihiko Kamura ◽  
Yutaka Fukuhara ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa
Keyword(s):  
Liquid Velocity ◽  
Bubbly Flow ◽  
Interfacial Area ◽  
Stereo Image ◽  
Axial Distance ◽  
Two Phase ◽  
Flow Measurements ◽  
Local Flow ◽  
Flow Parameters ◽  
Micro Gravity

This study aims at the measurements of the axial developments of flow parameters such as void fraction profile, interfacial area concentration and Sauter mean diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe by using a stereo image-processing method at normal- and micro-gravity conditions. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter, z/D = 5, 20, 40 and 60) at various flow conditions of superficial gas velocity (0.00840–0.0298 m/s) and superficial liquid velocity (0.138–0.914 m/s). The effect of gravity on radial distribution of bubbles and the axial developments of two-phase flow parameter was discussed in detail based on the obtained data and the visual observation.

Effect of Gravity on Phase Distribution Patterns of Bubbly Two-Phase Flow in a Vertical Mini Pipe

2010 ◽  
Author(s):  
Shunichi Watanabe ◽  
Yutaka Fukuhara ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Takashi Hibiki
Keyword(s):  
Two Phase Flow ◽  
Phase Distribution ◽  
Liquid Velocity ◽  
Interfacial Area ◽  
Stereo Image ◽  
Axial Distance ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Measurements ◽  
Axial Development

In relation to the development of the interfacial area transport equation, a precise database of the axial development of void fraction profile, interfacial area concentration and Sauter mean bubble diameter in an adiabatic nitrogen-water bubbly flow in a 5 mm-diameter mini pipe was constructed for normal and microgravity conditions using stereo image-processing. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter, z/D = 5.5, 34, 72 and 110) and with various flows: superficial gas velocity of 0.00434–0.0420 m/s, and superficial liquid velocity of 0.239–0.949 m/s. The effect of gravity on radial distribution of bubbles and the axial development of two-phase flow parameters is discussed in detail based on the obtained database and visual observation.

Effect of Gravity on Axial Development of Gas-Liquid Two-Phase Flows

2007 ◽  
Author(s):  
Junichi Uematsu ◽  
Kazuya Abe ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Takashi Hibiki
Keyword(s):  
Liquid Velocity ◽  
Interfacial Area ◽  
Visual Observation ◽  
Stereo Image ◽  
Axial Distance ◽  
Two Phase ◽  
Flow Measurements ◽  
Interfacial Area Concentration ◽  
Bubble Number ◽  
Axial Development

In pursuit of the development of the interfacial area transport equation, the axial development of void fraction profile, bubble number density, interfacial area concentration and Sauter mean diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured in normal and microgravity environments using stereo image-processing. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter, z/D = 5.0, 20, 40 and 60) at various flow conditions of superficial gas velocity (0.00823–0.0303 m/s) and superficial liquid velocity (0.147–0.907 m/s). The effect of gravity on the radial distribution of bubbles and the axial development of two-phase flow parameters is discussed in detail based on the measured data and the visual observation.

Axial Development of Vertical Upward Bubbly Flow in a Minipipe

2005 ◽  
Author(s):  
Tatsuya Hazuku ◽  
Naohisa Tamura ◽  
Norihiro Fukamachi ◽  
Tomoji Takamasa ◽  
Takashi Hibiki ◽  
...  
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Constitutive Relations ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Measurements ◽  
Local Flow ◽  
Interfacial Area Concentration ◽  
Drift Flux Model

Accurate prediction of the interfacial area concentration is essential to successful development of the interfacial transfer terms in the two-fluid model. Mechanistic modeling of the interfacial area concentration entirely relies on accurate local flow measurements over extensive flow conditions and channel geometries. From this point of view, accurate measurements of flow parameters such as void fraction, interfacial area concentration, gas velocity, bubble Sauter mean diameter, and bubble number density were performed by the image processing method at five axial locations in vertical upward bubbly flows using a 1.02 mm-diameter pipe. The frictional pressure loss was also measured by a differential pressure cell. In the experiment, the superficial liquid velocity and the void fraction ranged from 1.02 m/s to 4.89 m/s and from 0.980% to 24.6%, respectively. The obtained data give near complete information on the time-averaged local hydrodynamic parameters of two-phase flow. These data can be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow. As the first step to understand the flow characteristics in mini-channels, the applicability of the existing drift-flux model, interfacial area correlation, and frictional pressure correlation was examined by the data obtained in the mini-channel.

Interfacial area transport of bubbly flow under microgravity environment

2003 ◽  
Vol 29 (2) ◽  
pp. 291-304 ◽  
Author(s):  
T. Takamasa ◽  
T. Iguchi ◽  
T. Hazuku ◽  
T. Hibiki ◽  
M. Ishii
Keyword(s):  
Bubbly Flow ◽  
Interfacial Area ◽  
Microgravity Environment ◽  
Interfacial Area Transport

Axial Development of Local Flow Parameters in Bubbly Two-Phase Flow in Normal and Microgravity Conditions

2009 ◽  
Author(s):  
Yutaka Takata ◽  
Dong Chang Xing ◽  
Yutaka Fukuhara ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Interfacial Area ◽  
Axial Distance ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Measurements ◽  
Local Flow ◽  
Flow Parameters ◽  
Microgravity Conditions ◽  
Axial Development

In relation to the development of the interfacial area transport equation, a precise database of the axial development of void fraction profile, interfacial area concentration and Sauter mean bubble diameter in an adiabatic nitrogen-water bubbly flow in a 9 mm-diameter pipe was constructed for normal and microgravity conditions using stereo image-processing. The flow measurements were performed at four axial locations (axial distance from the inlet normalized by the pipe diameter, z/D = 5, 20, 40 and 60) and with various flows: superficial gas velocity of 0.00840–0.0298 m/s, and superficial liquid velocity of 0.138–0.914 m/s. The effect of gravity on radial distribution of bubbles and the axial development of two-phase flow parameters is discussed in detail based on the obtained database and visual observation.

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